how to understand this sentence in laravel

Question

Im trying to understand what the sentence $request->user()?->id ?: $request->ip() does in this function

protected function configureRateLimiting()
{
    RateLimiter::for('api', function (Request $request) {
            return Limit::perMinute(60)->by($request->user()?->id ?: $request->ip());
    });
}

According to my understanding it will limit the rate attempts to 60 by minute by either user id or IP address if there is not user logged in, Am I correct?

But then how will the ternary translates to a classical if sequence? something like this?

if (null !== $request->user()) {
    $request->user()->id;
} else {
    $request->ip();
}

Its the first time i see a ternary used in this way, can you give me some more examples of this use?

Thanks for your help!!!

Answer 1

there are two operators involved:

• null safety ?-> which either returns value of id property or null if user() is null

• ternary ?: which checks first part and returns it, if it is true or last argument if false

so, conversion to old syntax should look like this:

$tmp = null;
if ($request->user() != null) {
    $tmp = $request->user()->id;
}
if ($tmp) { // note id can be null theoretically
    $tmp = $tmp; // this part is hidden in `?:` effectively
} else {
    $tmp = $request->ip();
}
return Limit::perMinute(60)->by($tmp);

note: it is very important distinction between this code and yours - if id property is null while user() is not